The Brazilian, who was at Genoa last season, had hinted he would return home in January after receiving an offer from an unnamed club.
"I am to all intents and purposes a Vasco da Gama player now. There are no problems with the transfer and I can't wait to get my form back," the 25-year-old told Mediaset.
"Before coming to Italy I never had injuries, but due to the cold weather I've consistently had problems.
"This is why I'm happy to be going back to the warmth of Rio. I want to play because, like so many, I dream of a place in the Seleçao for the 2014 World Cup. I am a Vasco player now and I feel happy."